Create version-sweeper workflow YML file (dotnet#22931)

* Create version-sweep.yml

* Update .github/workflows/version-sweep.yml

Author: IEvangelist

.github/workflows/version-sweep.yml

@@ -0,0 +1,44 @@
+# This is a basic workflow to help you get started with Actions
+
+name: 'target supported version'
+
+# Controls when the action will run. 
+on:
+  # Triggers the workflow on push or pull request events but only for the master branch
+  schedule:
+  - cron: '0 0 1 * *'
+  workflow_dispatch:
+    inputs:
+      reason:
+        description: 'The reason for running the workflow'
+        required: true
+        default: 'Manual run'
+
+# A workflow run is made up of one or more jobs that can run sequentially or in parallel
+jobs:
+  # This workflow contains a single job called "build"
+  version-sweep:
+    # The type of runner that the job will run on
+    runs-on: ubuntu-latest
+
+    # Steps represent a sequence of tasks that will be executed as part of the job
+    steps:
+      # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
+      - uses: actions/checkout@v2
+
+      # Runs a single command using the runners shell
+      - name: 'Print manual run reason'
+        if: ${{ github.event_name == 'workflow_dispatch' }}
+        run: |
+          echo 'Reason: ${{ github.event.inputs.reason }}'
+
+      # Start the .NET version sweeper, scan projects/slns for non-LTS (or currrent) versions
+      - name: .NET version sweeper
+        id: dotnet-version-sweeper
+        uses: dotnet/[email protected]
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          owner: ${{ github.repository_owner }}
+          name: ${{ github.repository }}
+          branch: ${{ github.ref }}